One of the most treacherous places Nissa and the gang visit is a swamp, but this is where they finally learn more about the Crimson Orb.
In addition to the unstable ground they need to traverse, vines entangle the legs of their horses pulling them down, and their riders with them. They receive some help from the folks who live in the swamp, but it might not be enough. To learn more about this, read The Crimson Orb. www.amazon.com/dp/B00KWUO7E8